The present invention relates to a crankshaft supporting structure for in-line and V-shaped multicylinder internal combustion engines.
There is known a multicylinder internal combustion engine in which the crankshaft is rotatably supported by a plurality of journal walls integrally formed with the crankcase of the cylinder block and a plurality of bearing caps secured to the journal walls by bolts. The bearing caps are reinforced by a bridge to increase the rigidity of the crankshaft bearing assembly (see U.S. Pat. No. 3,841,203).
According to another known multicylinder internal combustion engine, a plurality of bearing caps supporting a crankshaft are secured respectively to a plurality of journal walls of the cylinder block, and the bearing caps are interconnected by a bridge. The crankshaft is supplied with lubricating oil from a lubricating oil system defined in the bearing caps and the bridge (see U.S. Pat. No. 1,759,147).
With the conventional multicylinder internal combustion engines, the rigidity of the crankshaft bearing assembly is of high rigidity since the bearing caps are interconnected by the bridge. The crankshaft bearing assembly is however disadvantageous in that the overall weight of the engine is increased.